Piston return apparatus for an anchor means inserting device



W. BAYER ET AL Feb. 10, 1970 PISTON RETURN APPARATUS FOR AN ANCHOR MEANS INSERTING DEVICE 2 Sheets-Sheet 1 Filed Sept. 1, 1967 v R m mm om A m Wa MMMW. m u M mm A M Feb. 10, 1970 w. BAYER" ET AL 13,494,532

PISTON RETURN APPARATUS FOR AN ANCHOR MEANS INSERTING DEVICE Filed'Sept. 1. 1967 I 2 Sheet-Sheet 2 [Wm Woman 8A YEK Ham-r M665? #1 7n qmmtfm United States Patent 3,494,532 PISTON RETURN APPARATUS FOR AN ANCHOR MEANS INSERTING DEVICE Wolfgang Bayer, Schaan, Liechtenstein, and Herbert Rangger, Frastanz, Austria, assignors to Hilti Aktiengesellschaft, Schaan, Liechtenstein Filed Sept. 1, 1967, Ser. No. 665,018 Claims priority, application Germany, Sept. 8, 1966,

Int. Cl. B25c 1/12 U.S. Cl. 227- 6 Claims ABSTRACT OF THE DISCLOSURE A device utilizing an explosive charge for driving anchoring means into position in a hard material and formed by a support member including a handle grip and a support arm and a barrel mounted on the support arm. The support arm is secured to and extends outwardly from the handle grip. The barrel has an axially extending bore which contains a piston. The piston is axially movable through the bore between the cartridge chamber end of the barrel and its muzzle end for driving the anchoring means into position. The barrel has an axially extending slot adjacent the support arm and a carrier finger extends through the slot into the bore of the barrel and is movable along the length of the slot. The barrel is pin connected at its muzzle end to the support arm. A linkage assembly is pin connected to the support arm and to the carrier finger for moving the finger through the slot. When the barrel is pivoted about its pin connection outwardly away from the support arm, the linkage assembly draws the carrier finger rearwardly through the slot and the finger, in turn, moves the piston from the muzzle end to the cartridge chamber end of the bore.

SUMMARY OF THE INVENTION The present invention is directed to a device for inserting anchoring or fastening means utilizing an explosive charge as the propelling means and, more particularly, it is directed to a piston return apparatus for use in such a device.

In previously known devices for inserting anchoring means, a piston, positioned within the barrel of the device, transmits the driving energy from the explosive charge to the anchoring means. The piston moves between a loaded position at the cartridge end of the barrel to a discharged position at the muzzle end. After each insertion of an anchoring means, carriers located within the barrel have been used to move the piston back to its loaded position. However, in these arrangements, the carrier is hand operated and the piston is returned to its loaded position by pulling the carrier rearwardly against a spring force. While this arrangement effectively returns the piston to its proper position, its hand operation increases the complexity of loading the device. Further, because it is hand operated, the mechanism is exposed on the exterior of the device and is subject to various difiiculties including the possibility that dust or other foreign objects might obstruct the guide means during construction work.

Accordingly, the present invention is directed to an arrangement for automatically returning the piston to its loaded position in the barrel.

Another object of the invention is to afford a guide assembly for returning the piston into the loaded position.

Moreover, another object of the invention is to provide a simple, efficient and easily operable arrangement of parts for returning the piston to its loaded position.

Therefore, the present invention is directed to a device 3,494,532 Patented Feb. 10, 1970 employing an explosive charge for driving anchoring means into a hard material, such as concrete and the like, and comprising a support member and a barrel. The support member comprises a handle grip and a support arm attached to and extending from the handle grip. The barrel has a bore extending axially between a cartridge chamber end and a muzzle end of the barrel. The barrel is mounted on the support arm. A piston is positioned within the bore of the barrel and is axially displaceable between its loaded position at the cartridge chamber end of the barrel and its discharged position at the muzzle end. The barrel is pin connected near its muzzle end to the support arm so that it can be pivotably moved away from the support arm. A slot extends axially along the barrel and a carrier finger extending into the bore of the barrel is movably positionable within the slot from its muzzle end to its cartridge chamber end. A link assembly is attached at one end to the carrier finger and at its other end to the support arm. When the barrel is pivoted upwardly away from the support arm, the linkage assembly draws the carrier rearwardly through the slot and, in turn, the carrier moves the piston from the muzzle end to the cartridge chamber end of the bore.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a device for inserting anchoring means incorporating the present invention; and

FIG. 2 is a partial side view showing the barrel of the device rotated upwardly away from its supporting member.

DETAILED DESCRIPTION As shown in FIG. 1, the device A for inserting anchoring means, such as nails, studs, bolts and the like, is composed of a support member 1 and a barrel 3. The support member 1 is comprised of a handle grip 1a and a support arm 2 secured to and extending longitudinally from the grip. The barrel 3 is mounted on the support arm 2 and has a bore 3a extending between a muzzle end 3b and a cartridge chamber end 3c of the barrel.

Near the muzzle end of the barrel, a plate member 4, shown partly in dashed lines, fits downwardly into the support arm 2 and is secured to it by means of a pin 5 within a pin slot guide 6. Though it is supported on the support arm 2, the barrel 3 is free to be moved upwardly from the arm at its cartridge chamber end in the direction shown by the arrow 1 by pivoting it about the pin connection 5 within the slot guide 6. At its muzzleend, the barrel contains a guide bushing 10 of a known type, for holding the anchoring means prior to insertion. A piston 9 is positioned within the bore 3a of the barrel, it is shown in full lines at the cartridge chamber end of the bore and in dotted lines identified by the reference numeral 9', at the muzzle end. When propelled by an explosive charge the forward end of the piston extends through the bushing 10 forcing the anchoring means into position.

A cartridge bearing 13 is located at the cartridge chamber end 30 of the barrel, and when the barrel is depressed against the material into which the anchoring means is to be inserted, the bearing is displaced in a known manner from the loading position shown in FIG. 1 into an ignition position which is located over the firing pin 45.

Along the lower portion of the barrel adjacent the support arm 2, a slot extends between the muzzle end and the cartridge end of the barrel. As illustrated in FIG. 1 a carrier finger 16 is located at the muzzle end of the slot and is secured by means of a guide pin 17 into a guide member 18 which is formed on the lower portion of the barrel 3 between the slot and the support arm 2. The carrier finger 16 is connected by means of a pin 19 to a lever arm 20 which extends rearwardly to a point below the cartridge chamber end of the barrel, where it is pivotally connected by means of a pin 21 to the support arm 2.

Within the support member 1 above the handle grip In there is a known pressure safety member, composed of a bolt which is arranged for axial displacement at the level of the barrel against a strong compression spring 31.

Positioned at the cartridge chamber end of the barrel 3 is a cartridge ejector of a type generally well known in the art. The cartridge ejector 35 is arranged in parallel relationship with the axis of the cartridge bearing 13 and the cartridge ejector acts against a spring 36 when in its operative position. At its lower end the cartridge ejector 35 has an arm 35a which engages the cartridge bearing 13 and an additional arm 35b into whose path of motion intersects a projecting edge 30a on the safety bolt extends when the barrel is pivoted upwardly, see FIG. 2 and safety bolt are depressed rearwardly into operative position.

The remaining features of the device do not form a part of the subject invention and, accordingly, are not described in detail at this point. In a preferred embodiment of the device, the support arm 2 may be provided with an additional longitudinally extending channel 40 which may be employed as a cartridge magazine.

When the device A is arranged to fire an anchoring member into a receiving material the piston 3a is disposed at the cartridge chamber end of the barrel and the pressure safety bolt is positioned rearwardly against the compression spring 31. When the explosive charge is ignited by the firing pin 45, the piston travels through the bore 3a driving the anchoring means from the guide bushing 10 into its receiving material and the piston assumes the position 9 indicated in dashed lines in FIG. 1. When the device is withdrawn from the receiving material, the spring 31 will return the barrel to the position shown in FIG. 1 and to reload the device A, the barrel is rotated upwardly so that its rear or cartridge chamber end swings away from the support arm, see FIG. 2, pivoting about the pin 5 in plate member 4 secured to the support arm. As the barrel 3 is rotated upwardly, the lever arm 20 draws the carrier finger rearwardly through the slot 15 guided by the pin 17 within the guide member 18. The carrier finger engages the piston 9 and moves it rearwardly until it assumes its loaded position at the cartridge chamber end of the bore as indicated in FIG. 1. After the device has been properly loaded and the piston is in its operative position at the cartridge chamber end of the bore, the barrel is rotated downwardly until it again rests on the support arm 2 and the lever arm 20 rides forwardly within the guide member 18 returning the carrier finger 16 back to its normal position near the muzzle end of the barrel. Accordingly, the piston is repositioned automatically during the loading operation of the device A and there is no need for any extra manipulation to relocate the piston in its loaded position.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A device for driving anchoring means into position comprising a supporting member, said supporting member comprising a handle and a support arm secured at one end to said handle and extending therefrom, a barrel having a bore extending axially therethrough between a cartridge chamber end and a muzzle end of the barrel, said barrel mounted on said support arm, a piston positioned within the bore of said barrel and axially displaceable therethrough between said cartridge chamber end and said muzzle end of said bore and adapted to drive anchoring means outwardly from the barrel, said barrel pivotally connected to said support member, said barrel having an axially extending slot therein, a carried finger extending through said slot into the bore of said barrel and normally positioned at the muzzle end of said barrel, means secured to said carrier finger and to said support member where-by when said piston is located at the muzzle end of said barrel it is returned to the opposite end of said bore by pivoting the barrel upwardly about its connection to said support member and said means moving said carrier finger rearwardly through said slot into engagement with said piston and moving said piston to the cartridge chamber end of said barrel, and thereby automatically returning the piston to the cartridge chamber end of the barrel when the barrel is rotatably displaced from the support member.

2. A device, as set forth in claim 1, wherein a plate member extends outwardly from said barrel and is pin connected to the end of said support arm remote from said handle whereby the barrel is rotatably positionable about said pin connection away from said support arm.

3. A device. as set forth in claim 2, wherein said means for moving said carrier arm within said barrel comprises a link assembly pin connected at one end to said support arm and at its other end to said carrier finger.

4. A device, as set forth in claim 3, wherein said link assembly comprises a lever arm pin connected to said carrier finger and to said support arm adjacent said handle.

5. A device, as set forth in claim 4, wherein a guide member is attached to and extends along said barrel adjacent said slot and a guide pin is attached to said carrier finger and secured within said guide member for guiding the carrier finger through the slot in said barrel.

. 6. A device, as set forth in claim 5, wherein a guide bushing is positioned within the muzzle end of said barrel and is adapted for holding anchoring means to be inserted by the device.

References Cited UNITED STATES PATENTS 3,348,751 10/1967 Henning 227l0 XR GRANVILLE Y. CUSTER, JR Primary Examiner 

